When printing on large sheets or on a web of print medium, several print jobs may be aggregated and imposed to fill the sheets or web as much as possible. As a consequence, on the same sheet or web there may be patterns or images that are different from each other, for example from different print jobs.
Furthermore, when print jobs are printed on a web that is wider than the patterns of the print jobs, the patterns may be imposed and printed in several longitudinal lanes along the web. The web may thereafter be slit to form narrower rolls, one for each lane, and therefore each roll having one row of patterns. It may be useful, for example when printing labels, that all the labels in one lane are the same and that they are spaced uniformly, such that they may subsequently be applied using an automatic device. The same occurs with other print jobs that may be subsequently handled in an automated way.
Print jobs may also be printed on a web of print medium in a frame by frame printing apparatus, for example a web press comprising a rotary printing drum with a flexible blanket. In this case, when printing jobs are imposed on the web of print medium, account has to be taken of the maximum frame length, i.e. the maximum size of the frames in the longitudinal direction of the web, which depends on the size of the blanket.